1. Field of the Invention
The present invention relates to an apparatus for automatically composing a musical piece.
2. Description of the Related Art
One of the most important considerations to be taken into account when designing an automatic composer is that the device in question should be capable of composing a musical piece which is familiar to people in general, i.e. one which is not mechanical in sound, but is full of musicality.
For example, U.S. Pat. No. 4,399,731 issued to E. Aoki on Aug. 23, 1983 discloses an automatic composer comprising means for randomly sampling individual pitch data from a set of pitch data, such as a twelve-note scale data, and means for checking whether the sampled data satisfies limited musical conditions. When the sample satisfies these conditions, it will be accepted as a melody note. If not, the sample is rejected as unsuitable for a melody note, and a new sample is taken from the set of pitch data and checked in turn. Thus, the basic process performed by this automatic composer is essentially one of trial and error. When pitch data are being randomly sampled, they constitute, at that point, a totally disordered sequence of pitches which is far removed from anything resembling good quality music; thus the chances of obtaining a melodic piece as a result, are negligible. In essence, therefore, the above apparatus provides a means for checking sampled data as to their musical conditions, or for selecting data by means of a condition filter. The selection standard is, consequently, a key factor in determining the quality of the music composed. If the selection of pitch data were too restrictive, the melodies generated would be lacking in variety. If, on the other hand, the selection process were too wide in scope, the original disordered sequence of pitches would be the predominant element in the melodies generated.
The above-mentioned automatic composer is thus more suitable for generating a melody which does not conform any existing style of music familiar to most people, and is primarily useful for music dictation i.e. solfeggio and/or performance exercise, since novel or unfamiliar music is, initially at least, difficult to read or play. The above automatic composer therefore clearly fails to satisfy the musical criteria outlined earlier.
The present invention contemplates the very function.
Other techniques of automatic composition are disclosed in U.S. Pat. No. 4,664,010 to A. Sestero, May 12, 1987 and WO No. 86/05619 by G. B. Mazzola et. al. Sept. 25, 1986. The former patent relates to a technique of converting a given melody into a different melody by performing a mirror or symmetry transformation of the given melody with respect to particular pitches. According to the latter patent application, a given melody is represented graphically by a set of locations in a two-dimensional space having a pitch axis (Y axis) and a time axis (X axis). A suitable transformation of the given melody is carried out with respect to the two axes, thereby developing a new melody formed by a sequence of pitches and a sequence of tone durations.
Each of the above techniques employs simply mathematical transformations such as symmetry conversion, and cannot be said to contemplate musical properties of melody; thus, the chances of achieving musical compositions of satisfactory quality are relatively low, when compared to the present invention.
Another automatic composer is disclosed, by the present inventor, in Japanese Patent laid open (Kokai) No. 62-187876, dated Aug. 17, 1987. This apparatus comprises a table representing frequencies of pitch transitions and a random number generator. In operation, tone pitches are successively developed from the outputs of the frequency table and the random number generator, to form a melody. The frequency table makes it possible to compose music which accords with the musical style designated by a user. Even this arrangement cannot be said, however, to carry out analysis and evaluation of musical properties of melody for musical composition.
Other relevant techniques are disclosed in U.S. Pat. No. 3,889,568 issued on June 17, 1975 concerning a system of chord progression programs, Japanese patent laid open (Kokai) No. 58-87593, May 25, 1983 and U.S. Pat. No. 4,539,882, Sept. 10, 1985 concerning an apparatus for automatically assigning chords to a melodic line.
The present invention aims to provide a novel and useful automatic composer and various apparatus associated therewith, far apart from the prior art.